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Theory of Planned Behavior/ Reasoned Action

Explaining human behavior

History and Orientation

Ajzen and Fishbein formulated in 1980 the theory of reasoned action (TRA). This resulted from attitude research from the Expectancy Value Models. Ajzen and Fishbein formulated the TRA after trying to estimate the discrepancy between attitude and behavior. This TRA was related to voluntary behavior. Later on behavior appeared not to be 100% voluntary and under control, this resulted in the addition of perceived behavioral control. With this addition the theory was called the theory of planned behavior (TpB). The theory of planned behavior is a theory which predicts deliberate behavior, because behavior can be deliberative and planned.

Core Assumptions and Statements

Theory of Reasoned Action suggests that a person's behavior is determined by his/her intention to perform the behavior and that this intention is, in turn, a function of his/her attitude toward the behavior and his/her subjective norm. The best predictor of behavior is intention. Intention is the cognitive representation of a person's readiness to perform a given behavior, and it is considered to be the immediate antecedent of behavior. This intention is determined by three things: their attitude toward the specific behavior, their subjective norms and their perceived behavioral control. The theory of planned behavior holds that only specific attitudes toward the behavior in question can be expected to predict that behavior. In addition to measuring attitudes toward the behavior, we also need to measure people’s subjective norms – their beliefs about how people they care about will view the behavior in question. To predict someone’s intentions, knowing these beliefs can be as important as knowing the person’s attitudes. Finally, perceived behavioral control influences intentions. Perceived behavioral control refers to people's perceptions of their ability to perform a given behavior. These predictors lead to intention. A general rule, the more favorable the attitude and the subjective norm, and the greater the perceived control the stronger should the person’s intention to perform the behavior in question.

Conceptual Model

Source: Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, p. 179-211.

Favorite Methods

Ajzen provides fairly clear instructions for designing theory of planned behavior questionnaires on his website. Ajzen uses a questionnaire to define the elements of behavior and uses direct observation or self-reports later on.

Scope and Application

Provide useful information for the development of communication strategies. This theory is also used in evaluation studies. Other usages of the model include: voting behavior, disease prevention behavior, birth control behavior (Jaccard & Davidson, 1972), consumption prediction.


Examples of items which can be researched with the theory of planned behavior are whether to wear a seat belt, whether to check oneself for disease and whether to use condoms when having sex.


Key publications

  • Aronson, E., Wilson, T.D. & Akert, R.M. (2003). Social Psychology. Upper Saddle River, NJ: Prentice Hall.
  • Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In J. Kuhl & J. Beckman (Eds.), Action-control: From cognition to behavior (pp. 11-39). Heidelberg: Springer.
  • Ajzen, I. (1987). Attitudes, traits, and actions: Dispositional prediction of behavior in personality and social psychology. In L. Berkowitz (Ed.), Advances in experimental social psychology (Vol. 20, pp. 1-63). New York: Academic Press.
  • Ajzen, I. (1988). Attitudes, personality, and behavior. Milton-Keynes, England: Open University Press & Chicago, IL: Dorsey Press.
  • Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211.
  • Ajzen, I. (2002). Perceived Behavioral Control, Self-Efficacy, Locus of Control, and the Theory of Planned Behavior. Journal of Applied Social Psychology, 32, 665-683.
  • Ajzen, I., & Fishbein, M. (in press). Questions raised by a reasoned action approach: Reply to Ogden (2003). Health Psychology.
  • Fishbein, M., & Ajzen, I. (in press). Theory-based behavior change interventions: Comments on Hobbis and Sutton (in press). Journal of Health Psychology.
  • Manstead, A. S. R., & Parker, D. (1995). Evaluating and extending the theory of planned behavior. In W. Stroebe & M. Hewstone (Eds.), European Review of Social Psychology (Vol. 6, pp. 69-96). Chichester, UK: John Wiley & Sons.
  • Notani, A. S. (1998). Moderators of perceived behavioral control's predictiveness in the theory of planned behavior: A meta-analysis. Journal of Consumer Psychology, 7, 247-271.
  • Sparks, P. (1994). Attitudes toward food: Applying, assessing and extending the theory of planned behavior. In D. R. Rutter & L. Quine (Eds.), The social psychology of health and safety: European perspectives (pp. 25-46). Aldershot, England: Avebury.
  • Taylor, S. and Todd, P., 1995. An integrated model of waste management behaviour: a test of household recycling and composting intentions. Environ. Behav. 27, 5, pp. 603–630.
  • Terry, D.J., Hogg, M.A. and White, K.M., 1999. The theory of planned behaviour: self-identity, social identity and group norms. Br. J. Social Psychol. 38, 3, pp. 225–244.
  • Thomas, C., 2001. Public understanding and its effect on recycling performance in Hampshire and Milton Keynes. Resour. Conserv. Recycl. 32, 3/4, pp. 259–274.
  • Parker, D., Manstead, A.S.R., Strading, S.G., Reason, J.T. and Baxter, J.S., 1992. Intentions to commit driving violations: an application of the theory of planned behaviour. J. Appl. Psychol. 77, pp. 94–101.
  • Phillips, P.S., Holley, K., Bates, M. and Fresstone, N., 2002. Corby waste not: an initial review of the UKs largest holistic waste minimisation project. Resour. Conserv. Recycl. 36, 1, pp. 1–33.
  • Price, J.L., 2001. The landfill directive and the challenge ahead: demands and pressures on the UK householder. Resour. Conserv. Recycl. 32, 3–4, pp. 333–348.
  • Read, A.D., 1999. Making waste work- making UK national solid waste strategy work at the local scale. Resour. Conserv. Recycl. 26, 3/4, pp. 259–285.
  • Read, A.D., 1999. A weekly doorstep recycling collection, I had no idea we could! Overcoming the local barriers to participation. Resour. Conserv. Recycl. 26, 3/4, pp. 217–249.

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